I have two of their sleeves, and I quite like them. IIRC, it’s dye-sub poly fabric on the outside, and some nice fluffy stuff on the inside - and put together by hand. I’ve got zipper versions myself, but I think drawstring is the better option for these.
There are photos of my sleeves on their site, near the bottom of the Feb. '19 gallery page. One is black with a bird skull I designed on each side, and the other is amber and brown, being close up photos of an SA Chocolatier key and a Kailh BOX Brown switch.
